Device for supplying a gas-air mixture to burners in heating apparatuses

Abstract

The device comprises a ventilation unit (4) connected with a gas-supplying valve unit (10) via a mixing duct (11). The fixed structures of the ventilation unit (4) and gas-supplying unit (10) and of the mixing duct (11) are of one piece construction (20), so as to give the device (1) an excellent structural compactness, which will make it adaptable to different types of burners (3) and boilers (2).

What is claimed is: 
     
       1. A device for supplying a gas-air mixture to burners in heating apparatuses, comprising: a ventilation unit (4) provided with a fan wheel (5) rotatable about a rotation axis and a fixed box-shaped portion (7) operatively engaging the ventilation unit (4) and having an inlet opening (8) communicating with the external environment and an outlet opening (9) to be connected with a burner (3);   a gas-supplying valve unit (10) comprising at least one valve seat and drive means (21) operating on said at least one valve seat (23, 24, 25, 26) to selectively open a gas passage through the at least one valve seat itself;   a mixing duct (11) communicating with the valve unit and the ventilation unit for bringing the valve unit (10) into fluid communication with the ventilation unit (4);   wherein said mixing duct (11) is defined by an auxiliary box-shaped portion (12) of flattened conformation projecting from the fixed box-shaped portion (7) of the ventilation unit (4), said auxiliary box-shaped portion being flattenend according to a median plane substantially perpendicular to the rotation axis of the fan wheel, and exhibiting a bottom wall carrying said at least one valve seat (23, 24, 25, 26) and said drive means (21) of the gas-supplying valve unit (10).   
     
     
       2. The device as claimed in claim 1, comprising a monolitic support body (20) defined by said auxiliary box-shaped portion (12) and the fixed box-shaped portion (7) of the ventilation unit (4) joined to each other in one piece. 
     
     
       3. The device as claimed in claim 1, wherein said fixed box-shaped portion (7) substantially is flattened according to a plane perpendicular to the rotation axis of said fan wheel (5). 
     
     
       4. The device as claimed in claim 1, wherein the fixed box-shaped portion (7) of the ventilation unit (4) comprises a base wall (13) provided with at least one perimetric bordering wall (14), as well as a first closing element (15) removably in engagement with said at least one perimetric bordering wall (14). 
     
     
       5. The device as claimed in claim 4, wherein said drive means (21) is fastened to an outer side of the bottom wall (16) facing away from an outer side of the base wall (13). 
     
     
       6. The device as claimed in claim 4, wherein a motor for operation of the fan wheel (5) is associated with said first closing element (15). 
     
     
       7. The device as claimed in claim 4, wherein the outlet opening (9) is formed in the base wall (13) of the fixed box-shaped portion (7) at a peripheral position relative to said fan wheel (5). 
     
     
       8. The device as claimed in claim 1, further comprising at least one interchangeable union element (22) engaged to the outlet opening (9) of the ventilation unit (4) for connectin it to the burner (3). 
     
     
       9. The device as claimed in claim 1, wherein the auxiliary box-shaped portion (12) comprises at least one second closing element (18) extending parallelly to the bottom wall (16) and detachably fixed to an auxiliary rim (17) integral with the bottom wall to delimit the mixing duct (11). 
     
     
       10. The device as claimed in claim 9, wherein the auxiliary rim (17) comprises a main portion (17a) projecting from said bottom wall (16) and an additional portion (17b) projecting outwardly from the base portion (13) of the fixed box-shaped portion (7) to circumscribe the inlet opening (8) of the ventilation unit (4). 
     
     
       11. The device as claimed in claim 1, comprising a plurality of valve seats (23, 24, 25, 26) interconnected with each other by outer stretches (27 a, b, c) and inner stretches (28 a, b, c) consecutively interconnected by passage openings (29) formed in said bottom wall (16), said outer and inner stretches being delimited by outer and inner bordering ribs (32) (33) formed in one piece with the bottom wall (16) and projecting outwardly and inwardly of the mixing duct (11) respectively. 
     
     
       12. The device as claimed in claim 11, wherein said drive means (21) is carried by a support element (34) fastened to an outer side of the bottom wall (16) and acting on the outer bordering ribs (32) to isolate the outer stretches (27 a, b, c) from the external environment. 
     
     
       13. The device as claimed in claim 11, further comprising at least one auxiliary closing element (35) fixed to the inner bordering ribs (33) to isolate the inner stretches (28 a, b, c) from the mixing duct (11).